Resin composition and method for producing same

Abstract

The present invention relates to a resin composition including 50-98 parts by mass of (A) a modified starch, 2-50 parts by mass of (B) polyvinyl alcohol, and 0.01-0.15 part by mass of (C) a compound represented by formula (1) or a salt thereof, the total content of component (A), component (B), and component (C) being 100 parts by mass, and the average amylose content of the modified starch (A) being at least 50% by mass.

Description

Description Title of invention: Resin composition and its manufacturing method Field of technology

[0001] The present invention relates to a resin composition used for food packaging containers and the like and a method for producing the same, a water-containing composition containing the resin composition and a method for producing the same, a coated article obtained by coating paper or film with the water-containing composition and a method for producing the same, a multilayer structure containing the coated article, a film or sheet made of the resin composition, a laminate containing the film or sheet, a packaging material made of the coated article or the multilayer structure, and a packaging tray or cup containing the film, sheet or laminate and a method for producing the same. BACKGROUND ART

[0002] Resin compositions containing modified starch and polyvinyl alcohol have been widely used in food packaging due to their excellent biodegradability (see, for example, JP 2002-532600 A). Prior art documents Patent documents

[0003] Patent Document 1: JP 2002-532600 Summary of the Invention Problems to be Solved by the Invention

[0004] Resin compositions used as containers for packaging these foods are required to have not only high oxygen barrier properties but also excellent impact strength to avoid breakage due to impact, etc. However, according to the studies of the present inventors, it has been found that even if an impact strength improver such as an inorganic substance such as talc or rubber particles is added to a resin composition containing modified starch and polyvinyl alcohol for the purpose of improving impact strength, sufficient impact strength cannot be obtained, and moreover, high oxygen barrier properties cannot be maintained.

[0005] Therefore, the object of the present invention is to provide a resin composition having excellent impact strength and oxygen barrier property and a method for producing the same, a water-containing composition containing the resin composition and a method for producing the same, and a method for producing a water-containing composition containing the resin composition. The present invention aims to provide a coated article obtained by coating a paper or film with an aqueous composition and a method for producing the same, a multilayer structure including the coated article, a film or sheet made of the resin composition, a laminate including the film or sheet, a packaging material made of the coated article or the multilayer structure, and a packaging tray or cup including the film or sheet or the laminate and a method for producing the same. [0006I] In order to solve the above problems, the present inventors have conducted extensive research into resin compositions containing modified starch (A) and polyvinyl alcohol (B), and have completed the present invention. Specifically, the present invention includes the following preferred embodiments:

[0007]

[0001] 50-98 parts by weight of modified starch (A), 2-50 parts by weight of polyvinyl alcohol (B), and 0.01 -0.15 parts by mass Formula (1): [C1] [wherein Ri represents an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 1 to 20 carbon atoms; R2 to R5 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 12 carbon atoms; and R6 represents a hydroxyl group or an alkoxy group having 1 to 12 carbon atoms] or a salt thereof (C), wherein the total content of the components (A), (B), and (C) is 100 parts by mass, and the average amylose content of the modified starch (A) is 50 mass% or more. [2] The resin composition according to

[0001] , wherein in the formula (1), Ri is an alkyl group having 1 to 6 carbon atoms or an aralkyl group having 7 to 9 carbon atoms. [3I] A resin composition according to

[0001] or [2], wherein the total content of the modified starch (A), the polyvinyl alcohol (B), and the compound represented by formula (1) or its salt (C) is 80 mass% or more based on the mass of the resin composition. [4J] A resin composition according to any one of

[0001] to [3], wherein the modified starch (A) is at least one selected from the group consisting of etherified starch, esterified starch, cationized starch, and crosslinked starch. [5I] A resin composition according to any one of

[0001] to

[0004] , wherein the modified starch (A) is at least one selected from the group consisting of etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms and esterified starch having a structural unit derived from a dicarboxylic acid anhydride. [6I] The resin composition according to any one of

[0001] to [5], wherein the polyvinyl alcohol (B) has a viscosity of 1 to 50 mPa·s at 20°C as a 4% aqueous solution measured in accordance with J-SZ 880 3. [7J] The resin composition according to any one of

[0001] to [6], further comprising 0.1 to 10 parts by mass of polyoxyalkylene (D) and / or 0.01 to 5 parts by mass of polyol plasticizer (E), wherein the total content of the components (A), (B), (C), (D) and (E) is 100 parts by mass. [8] A water-containing composition comprising the resin composition according to any one of

[0001] to [7], wherein the water-containing composition has a water content of 1 to 50 mass%. [9] A coated article obtained by coating the water-containing composition according to [8] on paper or film. [1 〇! A multilayer structure comprising the coating according to [9] and one or more layers (X).

[0011] [9] A packaging material comprising the covering material described in [9] or the multilayer structure described in [1 ○].

[0012] The water-containing composition according to [8] is extruded using an extruder. [9] A method for producing a coated article according to [9], comprising a step of coating a film or paper containing the coated article.

[0013]

[0001] A film or sheet made of the resin composition according to any one of [7] to [8].

[0014] A laminate comprising the film or sheet described in [1 3I] and one or more layers (X).

[0015] A packaging tray or cup comprising a film or sheet as described in

[0013] or a laminate as described in

[0014] .

[0016] A method for producing a packaging tray or cup according to

[0015] , comprising the steps of: using an extruder to mold a resin composition according to any one of

[0001] to [7] to obtain a film or sheet; laminating the obtained film or sheet with one or more layers (X) to obtain a laminate; and thermoforming the obtained laminate into a packaging tray or cup.

[0017] A method for producing a resin composition according to any one of

[0001] to [7], comprising a step of simultaneously mixing a compound represented by formula (1) or a salt thereof (C) with components other than said (C). [18I] A method for producing the resin composition according to any one of [1!] to [7I] or the water-containing composition according to [8], comprising the steps of: preparing a mixture by mixing components other than the compound represented by formula (1) or its salt (C) with the mixture; adding an aqueous solution of component (C) to the mixture; and optionally further drying the mixture. The resin composition of the present invention has excellent impact strength and oxygen barrier properties. Therefore, it can be suitably used as a material for food packaging and containers.

[0009] FIG. 1 is a schematic diagram showing the manufacturing process of the coated article in the examples. [Fig. 2] A schematic diagram of a twin-screw extruder used in the examples.

[0010] [Resin composition] The resin composition of the present invention comprises 50-98 parts by mass of modified starch (A), 2-50 parts by mass of polyvinyl alcohol (B), and 0.01 to 0.15 parts by mass of a copolymer of the formula (1): [Case 2] [wherein R i represents an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having ?-20 carbon atoms; R2 to R5 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 12 carbon atoms; and R6 represents a hydroxyl group or an alkoxy group having 1 to 12 carbon atoms] or a salt (C) thereof, wherein the total content of the components (A), (B), and (C) is 100 parts by mass, and the average amylose content of the modified starch (A) is 50 mass% or more. The compound represented by formula (1) may be referred to as compound (1), and compound (1) or its salt (C) may be collectively referred to as compound (C). Modified starch (A) may be referred to as component (A) or simply as (A). The same applies to other components. [0011I] The present inventors have investigated additive components capable of improving the impact strength of a resin composition containing modified starch and polyvinyl alcohol to + minutes. As a result, they have surprisingly found that when a resin composition having an average amylose content of 50% by mass or more and containing 50-98 parts by mass of modified starch (A) and 2-50 parts by mass of polyvinyl alcohol (B) is added with a small amount of 0.01-0.15 parts by mass of a compound represented by formula (1) or a salt thereof (C), the impact strength can be significantly improved while maintaining excellent oxygen barrier properties. Although the reason for this is unclear, it is believed that the compound represented by formula (1) or a salt thereof (C) has a similar effect to the modified starch (A). It is presumed that this is because it effectively interacts with the polymer (B) and polyvinyl alcohol (C), providing a local anti-plasticizing effect. [0012I] <Modified Starch (A)> The modified starch (A) is preferably at least one selected from the group consisting of, for example, etherified starch, esterified starch, cationized starch, and crosslinked starch.

[0013] Examples of starches include starches derived from cassava, corn, potato, sweetcorn, sago, pioca, sorghum, beans, bracken, lotus, water chestnut, wheat, rice, oats, arrowroot, turmeric, and peas. Among these, starches derived from corn and cassava are preferred, and starches derived from high-amylose corn are more preferred. Starches can be used alone or in combination of two or more types.

[0014] Examples of etherified starches include alkyl-etherified starches such as methyl-etherified starch, carboxyalkyl-etherified starches such as carboxymethyl-etherified starch, and hydroxyalkyl-etherified starches such as etherified starches having a hydroxyalkyl group having 2 to 6 carbon atoms. Allyl-etherified starch can also be used.

[0015] Examples of esterified starches include esterified starches having structural units derived from carboxylic acids, such as esterified starches having structural units derived from acetic acid; esterified starches having structural units derived from dicarboxylic anhydrides, such as esterified starches having structural units derived from maleic anhydride, esterified starches having structural units derived from phthalic anhydride, and esterified starches having structural units derived from octenylsuccinic anhydride; and esterified starches having structural units derived from oxoacids, such as nitrate-esterified starch, phosphate-esterified starch, and urea-phosphate-esterified starch. Other examples include xanthate-esterified starch, acetoacetate-esterified starch, etc.

[0016] Examples of cationized starch include a reaction product of starch with 2-diethylaminoethyl chloride and a reaction product of starch with 2,3-epoxypropyltrimethylammonium chloride.

[0017] Examples of cross-linked starches include formaldehyde cross-linked starch, epichlorohydrin cross-linked starch, phosphate cross-linked starch, acrolein cross-linked starch, etc.

[0018] From the viewpoint of easily improving film-forming properties when the resin composition is molded into a film, sheet, or coating, the modified starch (A) is preferably at least one selected from the group consisting of etherified starches having a hydroxyalkyl group having 2 to 6 carbon atoms and esterified starches having structural units derived from dicarboxylic acid anhydrides, and more preferably at least one selected from the group consisting of hydroxyethyl etherified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, esterified starches having structural units derived from maleic anhydride, esterified starches having structural units derived from phthalic anhydride, and esterified starches having structural units derived from octenyl succinic anhydride. The modified starches (A) can be used alone or in combination of two or more. In this specification, the number of carbon atoms stated before "starch" refers to the number of carbon atoms in the group substituted for one hydroxyl group in the starch (the group formed by modifying one hydroxyl group in the starch). For example, etherified starch having a hydroxyalkyl group having 2 to 5 carbon atoms indicates that the hydroxyalkyl group formed by modifying one hydroxyl group in the starch has 2 to 5 carbon atoms.

[0019] Etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms may be obtained by reacting starch with an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, etc. The average number of hydroxy groups used for modification is preferably 0.05 to 2 per glucose unit in the starch.

[0020] Modified starch (A) is modified starch (A) with an average amylose content of The average amylose content of the modified starch (A) is 50% by mass or more. If the average amylose content of the modified starch (A) is less than 50% by mass, sufficient impact strength, oxygen barrier properties, and molding processability tend not to be obtained. The average amylose content of the modified starch (A) is 50% by mass or more, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and particularly preferably 70% by mass or more. If the average amylose content is above the above lower limit, impact strength, oxygen barrier properties, and molding processability tend to be improved. The average amylose content of the modified starch (A) is usually 90% by mass or less. In this specification, the amylose content can be measured, for example, by the iodine coloration method described in "Starch 50 No. 4158-163 (1998) J." When one type of modified starch is used, the average amylose content indicates the amylose content of that one type of modified starch, and when two or more types of modified starches are used, the average amylose content is the weighted average of the amylose contents of the two or more types of modified starches. Therefore, for example, when two or more types of modified starches are used and the average amylose content is 50% by mass or more, modified starches with an amylose content of less than 50% by mass may be included. [0021I] The moisture content of the modified starch (A) is preferably 5 to 15% by mass.

[0022] Commercially available modified starch (A) can also be used. Typical commercially available examples of modified starch (A) include ECO FILM (trademark) and National 1658 (trademark), which are hydroxypropyl etherified starches manufactured by Ingredion.

[0023] The content of modified starch (A) is 50-98 parts by mass relative to 1.0 parts by mass of the total of components (A), (B), and (C). If the content of modified starch (A) is less than 50 parts by mass and more than 98 parts by mass, impact strength, oxygen barrier properties, take-up properties, non-adhesion properties, and bending resistance tend to decrease. In this specification, the total amount of components (A), (B), and (C) refers to the total amount including components (D) and / or (E), if these components are included. The content of the modified starch (A) is, relative to 100 parts by mass of the total of the components (A), (B), and (C), 50 parts by mass or more, preferably 60 parts by mass or more, more preferably 68 parts by mass or more, and even more preferably 70 parts by mass or more, and 98 parts by mass or less, preferably 95 parts by mass or less, and more preferably 92 parts by mass or less. When the content of the modified starch (A) is within the above range, impact strength, oxygen barrier properties, take-up properties, non-adhesion properties, and bending resistance are likely to be improved. In this specification, "take-off property" means the property that the resin composition (or water-containing composition) discharged from the die outlet of the extruder can coat conveyed paper or film without tearing, and "improved or increased take-off property" means that the resin composition can easily coat paper or film without tearing even when the paper or film is conveyed at high speed. Furthermore, "non-adhesion" means the property of not adhering well to a metal roll during production, and "improved or increased non-adhesion" means that adhesion to a metal roll during production is reduced. [0024I] <Polyvinyl alcohol (B)> The polyvinyl alcohol (B) contained in the resin composition of the present invention preferably has a degree of saponification of 80 to 99.9 mol %. When the degree of saponification of polyvinyl alcohol (B) is within the above range, it is easy to improve the impact strength, oxygen barrier property, and take-up property. The degree of saponification is more preferably 85 mol % or more, even more preferably 88 mol % or more, and still more preferably 95 mol % or more. In this specification, the degree of saponification refers to the molar fraction of hydroxyl groups relative to the total of hydroxyl groups and ester groups in polyvinyl alcohol (B). [0025I] Polyvinyl alcohol (B) may further contain other monomer units in addition to vinyl alcohol units. Examples of such other monomer units include monomer units derived from ethylenically unsaturated monomers. Examples of ethylenically unsaturated monomers include α-olefins such as ethylene, propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; unsaturated monomers having an acrylate group; methacrylic acid and its salts; unsaturated monomers having a methacrylate group; unsaturated monomers having the following structure: acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N,N-dimethyl acrylamide, diacetone acrylamide, acrylamide propane sulfonic acid and its salts, acrylamide propyl dimethylamine and its salts (for example, quaternary salts); methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamidopropane sulfonic acid and its salts, methacrylamide propyl dimethylamine and its salts (for example, quaternary salts); methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, 2,3-diamino vinyl ethers such as acetoxy-1-vinyloxypropane; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinyl halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and their salts or esters; vinyl silyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl carboxylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, Examples include vinyl ester monomers such as vinyl benzoate. The content of other monomer units is preferably 10 mol % or less, more preferably 5 mol % or less. Polyvinyl alcohol (B) can be used alone or in combination. The method for producing polyvinyl alcohol (B) is not particularly limited. For example, a method may be used in which a vinyl alcohol monomer and optionally other monomers are polymerized, and the resulting polymer is chlorinated to convert it into vinyl alcohol units. The polymerization method may be batch polymerization, semi-batch polymerization, continuous polymerization, semi-continuous polymerization, etc. Examples of the polymerization method include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Known methods can be used to chlorinate the polymer. For example, the chlorination can be carried out in a state where the polymer is dissolved in alcohol or aqueous alcohol. The alcohol that can be used in this case is preferably a lower alcohol such as methanol or ethanol. [0027I] The viscosity of a 4% aqueous solution of polyvinyl alcohol (B) at 20°C, measured in accordance with JIS Z 8803, is preferably 1 mPa•s or more, more preferably 2 mPa•s or more, even more preferably 3 mPa•s or more, and is preferably 50 mPa•s or less, more preferably 45 mPa•s or less, and even more preferably 35 mPa•s or less. When the viscosity of polyvinyl alcohol (B) is not less than the above lower limit, the oxygen barrier property is likely to be improved, and when the viscosity is not more than the above upper limit, the impact strength and take-up ability are likely to be improved. The viscosity of polyvinyl alcohol (B) can be measured using a viscometer, for example, by the method described in the Examples. [0028I] The content of polyvinyl alcohol (B) is 2 to 50 parts by mass per 100 parts by mass of the total of components (A), (B), and (C). If the content of polyvinyl alcohol (B) is less than 2 parts by mass and more than 50 parts by mass, the impact strength, oxygen barrier properties, take-up ability, non-adhesion property, and bending resistance tend to decrease. The content of polyvinyl alcohol (B) is 2 parts by mass or more, preferably 5 parts by mass or more, more preferably 8 parts by mass or more, per 100 parts by mass of the total of components (A), (B), and (C), and is 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 32 parts by mass or less, and even more preferably 30 parts by mass or less. When the content of polyvinyl alcohol (B) is equal to or greater than the above-mentioned lower limit, the impact strength, oxygen barrier properties, take-up properties, and bending resistance are likely to be improved, whereas when the content is equal to or less than the above-mentioned upper limit, the non-adhesion properties are likely to be improved. [0029I] <Compound (C) or a salt thereof> The resin composition of the present invention comprises a compound represented by formula (1): [C3] [wherein ^ represents an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms; R2 to R5 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 12 carbon atoms; and R6 represents a hydroxyl group or an alkoxy group having 1 to 12 carbon atoms] or a salt thereof (C). The resin composition of the present invention contains a small amount of compound (C), which significantly improves impact strength without impairing its excellent oxygen barrier properties. Furthermore, when the resin composition contains compound (C), it can maintain an excellent color tone even after long-term storage in a water-containing state. In this specification, "excellent color tone" means a low degree of coloring, for example, a low b value (yellowness index, Y) and "enhanced or improved color tone" means a reduced degree of coloring, for example, a reduced b value. In addition, the color tone after long-term storage in a hydrated state is sometimes simply referred to as the color tone after storage. [0030I] In R in formula (1), examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 2-ethylpropyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a tert-octyl group, an n-nonyl group, and an n-decyl group. From the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, alkyl groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, and a sec-butyl group, are preferred. An aryl group is preferred, and an alkyl group having 1 to 4 carbon atoms is more preferred. Examples of aryl groups having 6 to 20 carbon atoms include phenyl, tolyl, and naphthyl groups. From the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, aryl groups having 6 to 8 carbon atoms, such as phenyl, are preferred. Examples of aralkyl groups having 7 to 20 carbon atoms include benzyl and phenethyl groups. From the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, aralkyl groups having 1 to 9 carbon atoms, such as benzyl, are preferred. Among Ri in formula (1), from the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, the above alkyl groups having 1 to 6 carbon atoms or the above aralkyl groups having 7 to 9 carbon atoms are preferred.

[0031] In R2 to R5 in formula (1), examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group having 1 to 12 carbon atoms include those exemplified above as the alkyl group having 1 to 12 carbon atoms in 1, with an alkyl group having 1 to 4 carbon atoms being preferred. Examples of the alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, a neopentoxy group, an n-hexoxy group, an n-octoxy group, and the like, with an alkoxy group having 1 to 4 carbon atoms being preferred. Among R2 to R5 in formula (1), from the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferred, and a hydrogen atom is more preferred. In the formula (1), R6 is an alkoxy group having 1 to 12 carbon atoms. 2 Examples of the alkoxy group having 1 to 12 carbon atoms for R to R5 include those exemplified above, with an alkoxy group having 1 to 4 carbon atoms being preferred. Among R6 in formula (1), a hydroxyl group is preferred from the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage.

[0033] In a preferred embodiment of the present invention, compound (1) is a compound in which R is an alkyl group having 1 to 6 carbon atoms or an aralkyl group having 7 to 9 carbon atoms, R to R are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R is a hydroxyl group. When such a compound (1) is contained, the impact strength, oxygen barrier properties, and color tone after storage of the resin composition are easily improved. Specific examples of the compound (C) include methylparaben, ethylparaben, benzylparaben, n-propylparaben, isopropylparaben, n-butylparaben, and salts thereof. From the viewpoint of easily improving impact strength, oxygen barrier properties, and color tone after storage, methylparaben, ethylparaben, benzylparaben, n-propylparaben, and salts thereof are preferred. The compound (C) can be used alone or in combination of two or more.

[0035] The content of compound (C) is 0.01 to 0.15 parts by mass per 100 parts by mass of the total of components (A), (B), and (C). If the content of compound (C) is less than 0.01 parts by mass and exceeds 0.15 parts by mass, the impact strength, oxygen barrier properties, take-up properties, and non-adhesion properties tend to decrease. The content of compound (C) is 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.04 parts by mass or more, and 0.15 parts by mass or less, preferably 0.12 parts by mass or less, even more preferably 0.10 parts by mass or less, even more preferably 0.09 parts by mass or less, particularly preferably 0.08 parts by mass or less, and especially preferably 0.07 parts by mass or less. When the content of compound (C) is at least the above lower limit, the impact strength and color tone after storage are likely to be improved, and when the content of compound (C) is not more than the above upper limit, the impact strength and oxygen barrier property are likely to be improved. According to the present invention, even if only a small amount of compound (C) is contained, the impact strength, oxygen barrier property, and color tone after storage can be significantly improved.

[0036] <Polyoxyalkylene (D) and polyol plasticizer (E)> The resin composition of the present invention may further contain polyoxyalkylene (D) and / or polyol plasticizer (E). When polyoxyalkylene (D) and / or polyol plasticizer (E) are contained, impact strength, color tone after storage, take-up property, and non-adhesion property tend to be improved. Polyoxyalkylene (D) represents polyalkylene oxide and polyalkylene glycol, and is represented by the following formula (2): [C4] TR - 〇 20 ⑵ [wherein R is an alkylene group, and n is 1 or greater]. The polyoxyalkylene (D) may have two or more different types of structural units (2).

[0037] In formula (2), examples of the alkylene group include alkylene groups having 2 to 10 carbon atoms, such as ethylene, propylene, trimethylene, butylene, isobutylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene. Among these, from the viewpoint of easily improving impact strength, take-up ability, non-adhesion, and bending resistance, alkylene groups having 2 to 6 carbon atoms are preferred, and ethylene and / or propylene groups are more preferred. When n is 2 or more, these alkylene groups can be used alone or in combination.

[0038] In formula (2), n is preferably 5 or more, more preferably 50 or more, even more preferably 100 or more, and is preferably 120,000 or less, and more preferably 70,000 or less. When n is within the above range, impact strength, oxygen barrier properties, take-up properties, non-adhesion properties, and bending resistance are likely to be improved. When polyoxyalkylene (D) contains different structural units (2), the repeating number n of each structural unit may be the same or different.

[0039] Examples of polyalkylene oxides include polymers having structural units derived from alkylene oxides having 2 to 6 carbon atoms, such as polyethylene oxide, polypropylene oxide, polytrimethylene oxide (polyoxetane), polybutylene oxide, polyisobutylene oxide, or copolymers of monomers constituting these. Examples of polyalkylene glycols include polymers having structural units derived from alkylene glycols having 2 to 6 carbon atoms, such as polyethylene glycol, polypropylene glycol, polytrimethylene oxide, polyisobutylene oxide, or copolymers of monomers constituting these. Examples of the polyoxyalkylene (D) include methylene glycol, polybutylene glycol, polyisobutylene glycol, and copolymers of monomers constituting these. Among these, from the viewpoint of easily improving impact strength, take-up property, non-adhesion property, and bending resistance, the polyoxyalkylene (D) is preferably polyethylene oxide, polypropylene oxide, polyethylene glycol, polypropylene glycol, or copolymers of monomers constituting these. As the copolymer, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene glycol and propylene glycol, etc. are preferred. [0040I] The polyoxyalkylene (D) may contain structural units derived from monomers other than the structural unit (2), as long as the effects of the present invention are not impaired. When the polyoxyalkylene (D) is a copolymer, the polymerization form of the copolymer is not particularly limited, and may be any of a random, block, graft, or tapered structure. [0041I] The weight-average molecular weight of the polyoxyalkylene (D) is preferably 10,000 or more, more preferably 50,000 or more, and preferably 5,000,000 or less, more preferably 3,000,000 or less. When the weight-average molecular weight is within the above range, impact strength, oxygen barrier properties, take-up properties, non-adhesion properties, and bending resistance are likely to be improved. [0042I] Commercially available polyoxyalkylenes (D) can also be used. Typical examples of commercially available polyoxyalkylenes (D) include ALKOX (trademark) E-75G, ALKOX (trademark) L-11, ALKOX (trademark) L-6, and ALKOX (trademark) EP 1010 N, all manufactured by Meisei Chemical Industry Co., Ltd., and PEO (trademark) PE0-1 and PE0-2, all manufactured by Sumitomo Seika Chemicals Co., Ltd. [0043I] When the resin composition of the present invention contains polyoxyalkylene (D), the content of polyoxyalkylene (D) is preferably 0.1 part by mass or more, more preferably 0.5 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the total of the components (A), (B), (C), (D) and (E). When the content of polyoxyalkylene (D) is equal to or more than the above lower limit, the impact strength, color tone after storage, take-up property, non-adhesion property, and bending resistance are likely to be improved, and when the content is equal to or less than the above upper limit, the oxygen barrier property is likely to be improved. [0044I] The polyol plasticizer (E) can improve the flexibility of the resin composition and can therefore be used, in particular, to control hardness and softness. Examples of the polyol plasticizer (E) include sorbitol, maltitol, glycerol, mannitol, xylitol, erythritol, ethylene glycol, and propylene glycol. The polyol plasticizer (E) can be used alone or in combination of two or more. Among these, sorbitol is preferred from the viewpoint of easily improving impact strength, color tone after storage, oxygen barrier properties, take-up properties, non-adhesion properties, flexibility, and bending resistance. [0045I] When the resin composition of the present invention contains a polyol plasticizer (E), the content thereof is The polyol plasticizer (E) content is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, and is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less. When the content of the polyol plasticizer (E) is above the above lower limit, the flexibility of the resin composition is easily increased, and when it is below the above upper limit, the impact strength, color tone after storage, oxygen barrier properties, take-up properties, non-adhesion properties, and bending resistance are easily improved. As described below, since extrusion molding is possible in the present invention, the resin composition can be produced using water or the like as a plasticizer without using a polyol plasticizer. [0046I <Resin Composition> The resin composition of the present invention contains 50-98 parts by mass of modified starch (A), 2-50 parts by mass of polyvinyl alcohol (B), and 0.01-0.15 parts by mass of compound (C) relative to 100 parts by mass in total of components (A), (B), and (C), and since the average amylose content of component (A) is 50% by mass or more, it is possible to achieve both excellent impact strength and excellent oxygen barrier properties. Therefore, While having excellent elasticity, the resin composition of the present invention can effectively suppress the occurrence of breakage and other problems even when subjected to impact, and is also excellent in biodegradability. Furthermore, by containing compound (C), the resin composition of the present invention can also maintain an excellent color tone even after long-term storage in a water-containing state. Therefore, when a water-containing composition using water as a plasticizer is molded and processed, it can be used even after long-term storage with the addition of water. In a preferred embodiment of the present invention, the resin composition of the present invention also has excellent take-up properties and non-adhesion properties. For example, when producing a coated product, the resin composition can be produced at a high conveying speed, and damage due to sticking to a metal roll does not occur, resulting in a good appearance. Moreover, since the resin composition has excellent bending resistance, the penetration of liquids and the like through the folded parts after repeatedly bending the resulting molded product (e.g., a coated product) can be suppressed. Therefore, the resin composition of the present invention can be suitably used as a material for food packaging, containers, etc. [0047I] The resin composition of the present invention may further contain a fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof. Examples of fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof include stearic acid, calcium stearate, sodium stearate, palmitic acid, lauric acid, myristic acid, linoleic acid, and behenic acid. Among these, stearic acid, calcium stearate, and sodium stearate are preferred from the viewpoint of processability. The fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof may be used alone or in combination of two or more. When the resin composition of the present invention contains a fatty acid and / or a fatty acid salt thereof having 12 to 22 carbon atoms, the content in the resin composition is preferably 0.01 to 3 mass%, more preferably 0.03 to 2 mass%, and even more preferably 0.1 to 1 mass%, based on the mass of the resin composition. When the content of the fatty acid and / or the fatty acid salt thereof having 12 to 22 carbon atoms is within the above range, there is a tendency for the composition to be advantageous in terms of processability.

[0049] The resin composition of the present invention may further contain clay. Examples of clay include synthetic or natural layered silicate clays, such as montmorillonite, bentonite, Examples of clays include beidelite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magadite, kenyaite, stevensite, and volkonskoite. Clays can be used alone or in combination.

[0050] When the resin composition of the present invention contains clay, the content of clay in the resin composition is preferably 0.1 to 5 mass%, more preferably 0.1 to 3 mass%, and even more preferably 0.5 to 2 mass%, based on the mass of the resin composition. When the clay content is within the above range, there is a tendency for the composition to be advantageous in terms of transparency, color tone, and strength.

[0051] The resin composition of the present invention may contain a plasticizer (F) other than the polyol plasticizer (E). Examples of the plasticizer (F) include water, triolein, barley glycerol, epoxidized linseed oil, epoxidized soybean oil, tributyl citrate, acetyltriethyl citrate, glyceryl triacetate, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The plasticizer (F) may be used alone or in combination. Among these plasticizers (F), water is preferred from the viewpoint of obtaining good film-forming properties and coatability.

[0052] The water content (moisture content) in the resin composition is preferably 3 to 20 mass%, more preferably 4 to 18 mass%, and even more preferably 7 to 15 mass%, based on the mass of the resin composition, from the viewpoint of easily increasing the impact strength and oxygen barrier property of the resin composition. The water content can be determined, for example, by measuring using a heat-drying moisture meter at 130°C for 60 minutes.

[0053] The resin composition of the present invention may further contain additives, as necessary, such as fillers, processing stabilizers, weather resistance stabilizers, colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, flame retardants, other thermoplastic resins, lubricants, fragrances, antifoaming agents, deodorizers, extenders, release agents, mold release agents, reinforcing agents, crosslinking agents, mildew inhibitors, preservatives, and crystallization rate retarders.

[0054] In the resin composition of the present invention, the total content of the modified starch (A), the polyvinyl alcohol (B) and the compound (C) is preferably The total content of components (A), (B), and (C) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, and preferably 100% by mass or less. When the total content of components (A), (B), and (C) is within the above range, impact strength, oxygen barrier properties, color tone after storage, take-up properties, non-adhesion properties, and folding resistance are likely to be improved. As described above, the total content of components (A), (B), and (C) is the total content including components (D) and / or (E) when these components are contained. [0055I] The resin composition of the present invention may be in the form of pellets, a film, or a sheet. When the resin composition of the present invention is used as a film or a sheet, the thickness of the film is generally 5-100 μm, and the thickness of the sheet is generally 100 μm to 1,000 μm. The film or sheet may be a single layer or a multilayer (for example, a laminate as described below). In this specification, a resin composition in the form of pellets, a film, or a sheet is also included in the term "resin composition," and pellets, films, and sheets made of the resin composition may be referred to as a pellet-shaped resin composition, a film-shaped resin composition, and a sheet-shaped resin composition, respectively. In one embodiment of the present invention, the impact strength of the resin composition of the present invention is preferably 5 mN / jucm or more, more preferably 6 mN / jucm or more, even more preferably 8 mN / jucm or more, still more preferably 10 mN / jucm or more, particularly preferably 12 mN / jucm or more, and particularly preferably 14 mN / jucm or more. When the impact strength is equal to or greater than the above lower limit, the occurrence of breakage or the like is easily effectively suppressed even when subjected to impact. The upper limit of the impact strength is usually 100 mN / jucm or less. The impact strength can be measured using an impact strength measuring device after storing the resin composition at 23°C and 50% RH for 2 weeks to condition the humidity, and then measuring by, for example, the method described in the Examples.

[0057] In one embodiment of the present invention, the oxygen permeability (mL / min) of the resin composition of the present invention at 23°C - 50% RH is 2 - atm - 24 hr) is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. , and even more preferably 2.8 or less. When the oxygen permeability is equal to or less than the above upper limit, excellent oxygen barrier properties can be exhibited. The oxygen permeability can be measured by storing the resin composition at 23°C and 50% RH for two weeks and adjusting the humidity, and then measuring it with an oxygen permeability measuring device, for example, by the method described in the Examples. In this specification, "improved or enhanced oxygen barrier properties" means that the oxygen permeability is reduced, and "excellent oxygen barrier properties" means that the oxygen permeability is low. The resin composition of the present invention has a b-value after storage at 23°C for 90 days in a water content of 35±1% by mass, of preferably 35 or less, more preferably 30 or less, even more preferably 25 or less, even more preferably 20 or less, particularly preferably 18 or less, and particularly preferably 16 or less. When the b-value after storage is equal to or less than the above upper limit, the resin composition can have an excellent color tone even after storage. The lower limit of the b-value after storage is usually 10 or more. The b-value after storage (also referred to as yellowness index, 21) can be measured using a colorimeter after storage of the resin composition at 23°C for 90 days in a water content of 35±1% by mass, and can be measured, for example, by the method described in the Examples.

[0059] [Method for Producing Resin Composition] The resin composition of the present invention can be produced by a method comprising the step (I) of mixing the components constituting the resin composition, at least modified starch (A), polyvinyl alcohol (B), and compound (C). In a preferred embodiment of the present invention, the method for producing the resin composition comprises, in addition to step (I), a step (II) of extruding the mixture obtained in step (I), and a step (III) of cooling and drying the extruded mixture.

[0060] In step (I), the modified starch (A), polyvinyl alcohol (B) and compound (C), and optionally polyoxyalkylene (D) and / or polyol plasticizer (E), other components such as the fatty acid having 12 to 22 carbon atoms and / or its fatty acid salt, the clay, the plasticizer (F), and the additives can be mixed together. In one embodiment of the present invention, in step (I), it is preferred to simultaneously mix compound (C) with components other than compound (C). This method makes it easy to improve the impact strength, color tone after storage, oxygen barrier property, take-up property, non-adhesion property, and bending resistance of the resulting resin composition. Note that the components other than compound (C) refer to components (or raw materials) other than compound (C) that constitute the resin composition.

[0062] Step (I) is usually carried out using an extruder, in which the components are subjected to shear stress by a screw and mixed homogeneously while being heated by applying external heat to the barrel.

[0063] The extruder may be, for example, a twin-screw extruder. Twin-screw extruders may be either co-rotating or counter-rotating. The screw diameter may be, for example, 20 to 150 mm, and the ratio (L / D) of the extruder length (L) to the screw diameter (D) may be, for example, 20 to 50. The screw rotation speed is preferably 80 rpm or higher, more preferably 100 rpm or higher. The extrusion pressure is preferably 5 bar (0.5 MPa) or higher, more preferably 10 bar (1.0 MPa) or higher. Each component can be directly introduced into the extruder. Alternatively, the components may be premixed using a mixer and then introduced into the extruder.

[0064] In step (I), from the viewpoint of easily improving the film-forming properties and oxygen barrier properties of the resin composition, it is preferable to mix a plasticizer (F), preferably water, in an amount of preferably 0.1 mass% or more, more preferably 1 mass% or more, even more preferably 10 mass% or more, particularly preferably 15 mass% or more, and most preferably 20 mass% or more, relative to the mass of the mixture, and preferably 50 mass% or less, more preferably 45 mass% or less, and even more preferably 40 mass% or less. Here, the mass of the mixture indicates the total mass of the mixture including the plasticizer (F). In step (I), the plasticizer (F) may be introduced at an early stage of extrusion, and can be introduced before the heating temperature is reached, for example, when the temperature is below 100°C. The modified starch (A) is resistant to a combination of moisture, heat, and shear stress. In addition, by separately introducing a plasticizer (F), preferably water, the water-soluble polymer such as polyvinyl alcohol (B) can be dissolved, the resin composition can be softened, and the modulus and brittleness can be reduced. In step (I), the cooking treatment is preferably carried out by heating to a temperature of more than 100°C and not more than 150°C, more preferably from 115°C to 140°C. Here, the cooking treatment is a treatment for crushing and gelling starch granules. Heating can be carried out by applying heat from the outside to the barrels of the extruder. By applying a temperature that is changed stepwise to each barrel, heating to the desired temperature is possible. Cooking at a temperature above 120°C is advantageous in terms of processability. The cooked mixture is preferably heated for 85-180°C to prevent foaming. 20°C, preferably 90 to 11°C 0 It is preferable to push the mixture toward the die while lowering the temperature to 100°C. In addition, foaming can be prevented and moisture can be removed by venting the barrel.

[0067] The residence time in the extruder can be set depending on the temperature profile and screw speed, and is preferably 1 to 2.5 minutes.

[0068] In step (II) of extruding the mixture obtained in step (I), the molten mixture that has been forced through the extruder while being melt-kneaded is extruded through a die. The die temperature is preferably 85 to 120°C, more preferably 90 to 110°C.

[0069] In step (III) of cooling and drying the extruded mixture (melt), the mixture (melt) can be extruded into a film, sheet, or strand shape.

[0070] When the mixture is extruded into a film or sheet, the mixture can be extruded through a die for forming a film or sheet, and then cooled and dried while being taken up by a take-up roller. It is preferable to cool the mixture between the die and the roller to prevent it from sticking to the roller. Rollers for forming the film or sheet may be installed. The rolls may be made of, for example, rubber, resin, or metal. For drying, the rolls may be heated, and dehumidified air may be supplied during winding. In the case of the blown tube method, the dehumidified air can be used to expand the film or sheet as it exits the die. Talc can also be entrained in the air stream to prevent blocking of the film or sheet.

[0071] When the mixture is extruded into strands, the strands can be formed into pellets by extruding them through a strand nozzle with multiple holes and cutting them with a rotary cutter. To prevent the pellets from sticking together, vibration can be applied periodically or constantly, and moisture in the pellets can be removed by hot air, dehumidified air, or an infrared heater.

[0072] [Water-containing composition and method for producing same] The present invention includes a water-containing composition comprising the resin composition described above and having a water content of 1 to 50 mass %. In one embodiment of the present invention, in order to improve the film-forming properties of the resin composition, the water-containing composition may be prepared by adding water to the resin composition when the resin composition is coated on paper or a film.

[0073] In the present invention, since the resin composition has the above-mentioned composition, stickiness due to the addition of water can be suppressed, the take-up property and maximum draw ratio during the production of a coated product can be improved, and adhesion to a metal roll can be reduced (non-adhesion can be improved). The moisture content can be determined by measuring at 130 ° C for 60 minutes using a heat-drying moisture meter, for example, by the method described in the Examples. In this specification, the term "water-containing composition" means all water-containing resin compositions having a moisture content of 1 to 50 mass% measured by the above method. In other words, the water-containing composition may be prepared by adding water to a produced resin composition, and the water content of the resin composition itself at the time of production is within the above range. In other words, even if a resin composition contains water, it is included in the concept of a resin composition, but among resin compositions, a resin composition whose water content is specified as 1 to 50 mass % is called a water-containing composition. The water content of the water-containing composition of the present invention is preferably 5% by mass or more, more preferably 8% by mass or more, and preferably 45% by mass or less, more preferably 40% by mass or less. When the water content is within the above range, the impact strength, oxygen barrier property, take-up property, non-adhesion property, and bending resistance of the resulting molded article are likely to be improved. In this specification, the term "molded article" refers to a resin composition or a water-containing composition whose form has been changed, and includes, for example, a resin composition in the form of a sheet or film, a coated article obtained using the resin composition or the water-containing composition, a laminate, a multilayer structure, a packaging material, and the like.

[0075] In a preferred embodiment of the present invention, the water-containing composition of the present invention can be obtained by adding water to the resin composition and, for example, stirring and mixing. To prevent the resin compositions from sticking together and to allow the water to be absorbed by the entire pellets, it is preferable to add water in two or more batches while stirring. To maintain a constant water content, the water-containing composition may be stored in a sealed container. In another embodiment of the present invention, the water-containing composition may be produced by a method comprising the steps of: preparing a mixture by mixing components other than compound (C); adding an aqueous solution of compound (C) to the mixture; and optionally, further drying the mixture. A resin composition may be produced by such a method. Examples of methods for producing the mixture include the same methods as those for producing the resin composition described in the above section [Method for Producing Resin Composition]. The aqueous solution of compound (C) can be obtained, for example, by adding water to compound (C) and stirring and mixing, and the amount of water in the aqueous solution of compound (C) can be adjusted appropriately depending on the solubility of compound (C) and the water content of the resulting water-containing composition or resin composition. The drying temperature and drying time in the drying step can also be selected appropriately depending on the water content of the resulting water-containing composition or resin composition.

[0076] [Coated Article and Manufacturing Method Thereof] The present invention includes a coated article obtained by coating paper or film with the water-containing composition of the present invention. The coated article of the present invention has excellent impact strength and oxygen barrier properties because it contains the water-containing composition. Furthermore, even if it is formed from a water-containing composition that has been stored in a water-containing state for a long period of time, it can have an excellent color. Furthermore, the preferred In this embodiment, it is possible to achieve both high take-up property and non-adhesion during production, which are normally difficult to achieve at the same time, and therefore production can be carried out at a high conveying speed while suppressing damage to the coated material due to sticking to the metal roll, thereby improving the yield rate and production efficiency.In addition, the film is also excellent in bending resistance and biodegradability. When the water-containing composition is coated on paper, the paper is not particularly limited, and examples thereof include kraft paper, fine paper, construction paper, glassine paper, parchment paper, synthetic paper, white cardboard, manila cardboard, milk carton base paper, cup base paper, ivory paper, silver paper, tissue paper, cardboard, and rayon paper. The thickness of the paper in the coating is not particularly limited, and is preferably 1 to 500 μm, more preferably 10 to 300 Atm. When the thickness of the paper in the coating is within the above range, the take-up speed during production of the coated product can be increased, and productivity is likely to be improved. When the water-containing composition is coated on a film, the film is not particularly limited, and examples thereof include polyethylene terephthalate (PET) film, biaxially oriented polypropylene (BOP) film, polyethylene (PE) film (preferably low-density polyethylene (LD PE) film), polylactic acid film, etc. The thickness of the film in the coating is not particularly limited, and is preferably 1 to 500 μm, more preferably 10 to 300 μm, and even more preferably 50 to 100 μm. The thickness of the aqueous composition in the coated article of the present invention is preferably 1 to 300 μm, more preferably 5 to 10 μm, and even more preferably 10 to 50 μm. When the thickness of the aqueous composition in the coated article is within the above range, good film-forming properties and oxygen barrier properties are easily obtained, the impact strength of the coated article is easily improved, and sticking to metal rolls during production is easily suppressed.

[0080] In one embodiment of the present invention, the oxygen permeability of the coating of the present invention can be selected from the same range as the oxygen permeability of the resin composition. The meaning and measuring method of the oxygen permeability are also the same as those of the resin composition.

[0081] The method for producing the coated article of the present invention is not particularly limited as long as it is a method that can coat paper or a film with a water-containing composition. The water-containing composition can be produced by a method including a step (referred to as step (A)) of using an extruder to coat the water-containing composition on a film or paper transported by a take-off machine. In one embodiment of the present invention, in step (A), the water-containing composition is charged into an extruder. Examples of extruders include single-screw extruders and twin-screw extruders. The extruder has a screw diameter of, for example, 20 to 150 mm, an L / D ratio of the extruder length (L) to the screw diameter (D) of, for example, 15 to 50, and a screw rotation speed of preferably 80 rpm or more, more preferably 100 rpm or more. The cylinder temperature in the extruder may be, for example, 80 to 120°C, preferably 90 to 110°C.

[0083] The aqueous composition introduced into the extruder is plasticized and discharged from the die outlet. Meanwhile, a paper or film is transported by a take-up machine, preferably a roller-type take-up machine. The aqueous composition discharged from the die outlet is coated onto the transported paper or film to obtain a coated product. The obtained coated product is transported while being pressed against the paper or film between multiple rolls, including a metal roll, and can be wound into a roll by a winder. Examples of the multiple rolls include a pressure roll, a cast roll, and a touch roll, and the cast roll is usually a metal roll (roll made of metal). In this case, in the present invention, the adhesion between the coated aqueous composition and the metal roll is low, so the peelability from the metal roll is high, and it is possible to effectively prevent the aqueous composition in the coated product from sticking to the metal roll and causing damage, etc. In addition, when producing a coated product, moisture evaporates, etc., so the moisture content of the hydrous composition after coating decreases compared to that before coating. However, it is preferable that the moisture content of the hydrous composition after coating also falls within the suitable range described above as the moisture content of the hydrous composition.

[0084] In step (A), the draw ratio represented by the following formula (X) is preferably 5 to 20. When a coated product is produced at such a draw ratio, productivity is improved, and a coated product having excellent adhesion between the paper or film and the water-containing composition, oxygen barrier properties, and impact strength is easily obtained. The flow rate at the die outlet of the extruder is expressed as above by (discharge rate) / ((lip opening)×(die width)). When the output is expressed as mass per unit time, the output is preferably 1 to 500 kg / hr, more preferably 5 to 200 kg / hr, the lip opening is preferably 0.01 to 5 mm, more preferably 0.1 to 1 mm, and the die width is preferably 100 to 3000 mm, more preferably 200 to 2000 mm. In the present invention, since the water in the aqueous composition evaporates during the above production process, the moisture content of the aqueous composition in the resulting coated product is reduced compared to before production. Draw ratio = (take-off speed of the take-off machine) / (flow rate at the die outlet of the extruder) (X)

[0085] [Multilayer structure and packaging material containing the coating] The present invention includes a multilayer structure containing the coating and one or more layers (X). Examples of the layer (X) include a film, paper, or adhesive. When there are two or more layers (X), the layers (X) may be the same or different. The multilayer structure of the present invention has multiple layers (X), but the number of layers is not particularly limited and may be, for example, 3 to 10 layers. Examples of the film and paper include the films and papers exemplified in the section [Coated product and manufacturing method thereof].

[0086] Examples of adhesives that may be included in the multilayer structure include acrylic adhesives, urethane adhesives, epoxy adhesives, vinyl acetate adhesives, ethylene-vinyl acetate adhesives, vinyl chloride adhesives, silicone adhesives, nitrile cellulose adhesives, phenol adhesives, polyvinyl alcohol adhesives, melamine adhesives, and styrene adhesives.

[0087] In a preferred embodiment of the present invention, the multilayer structure has a layer structure in the following order: film / adhesive / water-containing composition / paper / adhesive / film. In this embodiment, the type of film or paper is not particularly limited, but the film is preferably a polyethylene film.

[0088] The present invention includes a packaging material comprising the coating or multilayer structure of the present invention. The packaging material is excellent in impact strength, oxygen barrier properties, adhesion between the water-containing composition and paper or film, biodegradability, and bending resistance, and is therefore suitable for use as a packaging material for food. You can be there.

[0089] [Film or Sheet Made of Resin Composition and Laminate Including the Film or Sheet] The present invention includes a film or sheet made of a resin composition (a film-like resin composition or a sheet-like resin composition). As described above, the film or sheet of the present invention has excellent impact strength and oxygen barrier properties.

[0090] In one embodiment of the present invention, the oxygen permeability and impact strength of the film or sheet of the present invention can be selected from the same ranges as those of the oxygen permeability and impact strength described in the above <Resin Composition> section, respectively.

[0091] The method for producing the film or sheet of the present invention is not particularly limited, but examples thereof include the method for obtaining a film or sheet from the resin composition described above in the section [Method for producing resin composition].

[0092] The present invention includes a laminate comprising a film or sheet and one or more layers (X). The layer (X) may be, for example, the same as the layer (X) described in the section [Multilayer structure and packaging material containing the coating]. In a preferred embodiment of the present invention, the laminate preferably has a layer structure in which a sheet- or film-like resin composition layer / an adhesive layer / a substrate layer are laminated in this order. The adhesive layer is made of an adhesive, and the substrate layer is made of, for example, a film.

[0093] The method for producing the laminate of the present invention is not particularly limited, but it is preferably produced by lamination. For example, when the laminate has a sheet- or film-like resin composition layer / adhesive layer / substrate layer in this order, a method including the steps of co-extruding the adhesive layer and the substrate layer, and then coating the adhesive layer side onto the sheet- or film-like resin composition layer can be mentioned. Other examples include a method including the steps of extruding the adhesive layer and then coating the adhesive layer between the sheet- or film-like resin composition layer and the substrate layer; or a method including the steps of coating a solution or dispersion of an adhesive onto a sheet- or film-like resin composition layer or substrate layer with a gravure roll or the like, followed by drying, and then bonding the adhesive layer side to the other sheet- or film-like resin composition layer or substrate layer to which no adhesive is applied. and a step of bringing the substrate into close contact with the substrate.

[0094] In one embodiment of the present invention, the step of co-extruding the adhesive layer and the base layer is carried out using, for example, a two-layer co-extrusion cast film-forming equipment (extruder manufactured by the Plastics Engineering Research Institute). (Extruder (a) for base layer: single screw, screw diameter 40 mm, L / D = 32; extruder (b) for adhesive layer: single screw, screw diameter 32 mm, L / D = 26) can be used. The temperature conditions of the extruder can be set appropriately depending on the thermoplastic resin used. For example, when extruding PET (polyethylene terephthalate) using extruder (a) for base layer, the cylinder temperature can be set to 250-270°C, the adapter temperature to 270°C, and the die temperature to 275°C. Also, when extruding polyolefin using extruder (b) for adhesive layer, the cylinder temperature can be set to 175-270°C. 0 C sThe adapter temperature can be 270°C and the die temperature can be 275°C. The absolute value of the difference between the die temperature of extruder (a) and the die temperature of extruder (b) is preferably within 10°C, more preferably 0°C. For example, when the optimum die temperatures differ between the resin used in extruder (a) and the resin used in extruder (b), it is preferable to adjust the die temperature by adopting the resin with the higher optimum die temperature.

[0095] Thereafter, in the step of coating the adhesive layer side onto a sheet- or film-like resin composition, for example, a method can be employed in which the adhesive layer side of the co-extruded laminate is coated onto the sheet- or film-like resin composition while being taken up, and then the two are laminated using nip rolls. The take-up speed is preferably 1 to 50 m / min. Although the preferred extruders are described above, the type, screw diameter, and l / D of the extruder can be changed as appropriate.

[0096] [Packaging Container and Manufacturing Method Thereof] The present invention encompasses a packaging container, particularly a packaging tray or cup, comprising the film or sheet of the present invention or the laminate of the present invention. The packaging container may consist solely of the laminate of the present invention, or may be a composite of the laminate and other materials. For example, the laminate of the present invention can be thermoformed into a packaging container.

[0097] In one embodiment of the present invention, the packaging container of the present invention, in particular a packaging tray or cup, The cup can be produced by a method including the steps of: molding the resin composition using an extruder to obtain a film or sheet; laminating one or more layers (X) onto the obtained film or sheet to obtain a laminate; and thermoforming the obtained laminate into a packaging tray or cup. [0098I] As a step of molding the resin composition using an extruder to obtain a film or sheet, for example, the film or sheet molding method described above in the section [Method for producing a resin composition] can be used. As a step of laminating one or more layers (X) onto the obtained film or sheet to obtain a laminate, for example, the laminate manufacturing method described above in the section [Film or sheet made of a resin composition and laminate containing the film or sheet] can be used.

[0099] In the process of thermoforming the laminate into a packaging tray or cup, the thermoforming method is not particularly limited, but examples include general vacuum forming, pressure forming, and applications of these, such as the plug-assisted method in which a plug is brought into contact with one side of the laminate to form it, and the so-called multi-mold forming method in which a pair of male and female molds are brought into contact with both sides of the laminate to form it. Methods for heating and softening the laminate before forming include non-contact heating and direct heating, and non-contact heating includes radiant heating using an infrared heater or the like. Direct heating can be achieved by known heating methods, such as hot plate heating in which the laminate is brought into direct contact with a hot plate.

[0100] The packaging container of the present invention has excellent impact strength and oxygen barrier properties, and is therefore particularly suitable for use as a packaging container for food.

[0101] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0102] <Test Method> (1) Evaluation method of impact strength The sheet-shaped resin compositions (sheets) obtained in the examples and comparative examples were heated at 23°C for 50 After storing the specimens at 2% RH for 2 weeks to adjust the humidity, they were cut into 10 x 10 cm sections and then stored at Toyo Seiki. The impact strength was measured using a film impact tester manufactured by Epson Corporation.

[0103] (2) Measurement of oxygen permeability The sheet-shaped resin compositions (sheets) obtained in the examples and comparative examples were each stored at 23°C and 50% RH for 2 weeks to condition the humidity, and then attached to an oxygen permeability measuring device to measure the oxygen permeability. The measurement conditions were as follows: Device: MOCO N OX-TRAN 2 / 2 manufactured by Modern Controls J Temperature: 23 °C Humidity on oxygen supply side and carrier gas side: 50% RH Oxygen pressure: 1.0 atm Carrier gas pressure: 1.0 atm

[0104] Oxygen permeability is 5.0 ( m L - 20 / £ m / m 2 When the oxygen barrier property is less than 100% (- atm - 24 hr), the oxygen barrier property can be evaluated as good.

[0105] (3) Evaluation method for color tone (b value) Water was added to the pellet-shaped resin compositions obtained in the Examples and Comparative Examples so that the water content was 35% by mass, and the pellets and water were stirred and allowed to absorb water so that they were uniform. In Examples 1 and 4, n-propylparaben sodium salt (5 g) was dissolved in water in an amount that gave a water content of 35% by mass, and the obtained aqueous solution of n-propylparaben sodium salt was added to the pellet-shaped resin composition, and the pellets and water were stirred and allowed to absorb water so that they were uniform. The water content was measured using a heat-drying moisture meter HR 73J manufactured by Mettler-Toledo. 0 The content of the resin composition pellets was measured at 23°C for 60 minutes, and it was confirmed to be 35±1% by mass. To prevent evaporation of water, the pellets were sealed in aluminum pouches and stored at 23°C for 3 months (90 days). After that, the b value (yellowness index, 21) of the pellet-shaped resin composition pellets after storage was measured using a ZE-2000J colorimeter manufactured by Nippon Denshoku Industries Co., Ltd.

[0106] (4) Viscosity measurement method for polyvinyl alcohol (B) The polyvinyl alcohol in the examples and comparative examples was measured in accordance with JIS Z 880 3 (Falling Ball Viscometer) and J SK 672 6 (Testing Method for Polyvinyl Alcohol). A 4% aqueous solution of polyvinyl alcohol (B) was prepared, and its viscosity was measured at 20°C using a Hoebler viscometer. 0 C)

[0107] (5) Materials used <High amylose modified starch (A-1)> • ECO FILM (trademark): Corn starch modified with propylene oxide, amylose content 70% by mass, manufactured by Ingredients Corporation <Low amylose modified starch (A-2)> ■ Nati 〇 na I 1 658 (trademark): Corn starch modified with propylene oxide, amylose content 20% by mass, manufactured by ngredi 〇 n

[0108] <Polyvinyl alcohol (B)> - ELVAN 0 L (trademark) 71-30: Polyvinyl alcohol resin, degree of salinity 99% or more, viscosity 27-33 mPa • s (20 °C, 4% aqueous solution), manufactured by Kuraray Co., Ltd. • Kuraray Poval (trademark) 5-98: Polyvinyl alcohol resin, degree of salinity 9.8m. 1%, viscosity 5mPa-s (20°C, 4% aqueous solution), manufactured by Kuraray Co., Ltd. • Kuraray Poval (trademark) 3-98: Polyvinyl alcohol resin, degree of salinity 9.8m. 1%, viscosity 3mPa-s (20°C, 4% aqueous solution), manufactured by Kuraray Co., Ltd.

[0109] <Additional ingredients> (Compound (C)) • n-Propylparaben sodium salt: Ueno Pharmaceutical Co., Ltd. • n-Propylparaben: Manufactured by Ueno Pharmaceutical Co., Ltd. • Methylparaben: Manufactured by Ueno Pharmaceutical Co., Ltd. Benzylparaben: Manufactured by Ueno Pharmaceutical Co., Ltd. (Compounds other than (C)) Benzoic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Sorbic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Propionic acid, manufactured by Tokyo Chemical Industry Co., Ltd. Sodium benzoate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Impact strength improver 1: Talc, manufactured by Nippon Talc Co., Ltd., product name "Nano Ace (trademark) J Impact strength improver 2: Silicone acrylic rubber particles, manufactured by Mitsubishi Chemical Corporation, product name "Metablen S-2030 (trademark)"

[0110] (Compound (D)) Polyethylene oxide (PEO) resin: Weight average molecular weight 1 million, manufactured by Meisei Chemical Industry Co., Ltd., product name "ALKOX (trademark) L-11J"

[0111] (Compound (E)) Sorbitol: Manufactured by Bussan Food Science Co., Ltd., product name "Sorbitol S.G.J.

[0112] <Example 1> (Resin Composition) Raw materials ECO FILM™ (9.795 kg), Kuraray Poval™ 5-98 (200 g), and n-propylparaben sodium salt (5 g) were mixed in a tumbler mixer for 2 hours, and the resulting mixture was fed to a twin-screw extruder connected to a liquid pump. Figure 2 shows a schematic diagram of the twin-screw extruder used in Example 1, and Table 1 shows the screw diameter, L / D ratio, rotation speed, operating mode, and temperature profile of the extruder.

[0113] [Table 1]

[0114] Screw diameter: 27 mm L / Dh: 48 Screw rotation speed: 500 rpm Operation method: Co-rotating (interlocking self-wiping) method [0115I] Specifically, the resulting mixture was fed into the barrel through a hopper at C1 via a weight feeder of a twin-screw extruder at a rate of 3.5 kg / hr. Water was injected into the barrel at a flow rate of 26 g / min through a liquid pump (L) at C4. The temperature range from C5 to C9 is the cooking range, and complete pregelatinization of starch was achieved within this range. The extruded product was extruded through a film-forming die located after C1 and then taken up on a take-up roller. During take-up, the sheet was dried and cooled by heating the roll and supplying dehumidified air. After drying and cooling, a sheet-shaped resin composition (sheet) with a thickness of 100 μm was obtained.

[0116] (Coating) When extrusion was performed in the same manner as above, the film-forming die was replaced with a multi-hole strand nozzle and rotary cutter to form strands of the mixture into pellets. Because the pellets contained excess moisture, they were constantly vibrated and hot air was used to remove the moisture to prevent sticking. Water was added to the resulting pellet-like resin composition until the water content reached 35% by mass relative to the mass of the resin composition. During the water addition, the water was added in multiple batches while stirring with a tumbler mixer for 15 minutes to prevent sticking between the pellets and to ensure uniform absorption of water throughout the pellets. After stirring, the pellets were placed in a polyethylene bag, sealed, and left to stand at room temperature for 6 hours to prevent water evaporation. In this way, hydrous pellets (hydrous composition) with a moisture content of 35% by mass were obtained. The moisture content was measured using a Mettler-Toledo heated and dried moisture meter HR 73 J. 0The moisture content of the pellets was confirmed by measuring the moisture content at 1000 K for 60 minutes at 1000 K. The obtained moisture-containing pellets were then fed into a single-screw extruder 2 shown in FIG. 1 and extruded through a film-forming die 3. The moisture-containing composition 4 extruded from the outlet of the die 3 was then coated onto paper 5, which was being transported by a roller-type take-up machine (not shown). The coated product 6 was immediately pressed against the paper 5 (substrate) through a pressure roll (rubber) 7a, a cast roll (metal) 7b, and a touch roll (rubber) 7c, and then wound into a roll using a winder (not shown). The details of the single-screw extruder and its operating conditions, as well as the temperature profile (Table 2), are shown below. Single-screw extruder: Extruder manufactured by the Institute of Plastics Engineering (40 mm diameter, L / D = 2 5) [Table 2] •Discharge rate: 20 kg / hr Die: 450mm wide coat hanger die, lip opening: 0.2mm •Die-to-cast roll distance (air gap): 150mm Paper: Hakugin (uncoated paper, thickness 70 mm) manufactured by Nippon Paper Industries Co., Ltd.

[0117] The obtained coating had a good appearance with no uneven thickness or foreign matter.

[0118] Example 2 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (6.995 kg), Kuraray Poval (trademark) 5-98 (3.00 kg), and n-propylparaben sodium salt (5 g) were used as raw materials.

[0119] Example 3 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (8.995 kg), ELVAN OL (trademark) 71-30 (1.00 kg), and n-propylparaben sodium salt (5 g) were used as raw materials.

[0120] Example 4 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 3, except that ECO FILM (trademark) (6.746 kg) and National I 1658 (trademark) (2.249 kg) were used as the starch. <Example 5> A sheet-shaped resin composition, a water-containing composition and a coated article were obtained in the same manner as in Example 3, except that Kuraray Poval (trademark) 3-98 (1.00 kg) was used as the polyvinyl alcohol (B).

[0122] Example 6 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.999 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and n-propylparaben sodium salt (1 g) were used as raw materials.

[0123] Example 7 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.995 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and n-propylparaben sodium salt (5 g) were used as raw materials.

[0124] Example 8 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.990 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and n-propylparaben sodium salt (10 g) were used as raw materials.

[0125] Example 9 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 7, except that n-propylparaben was used instead of n-propylparaben sodium salt.

[0126] Example 1 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 7, except that methylparaben was used instead of n-propylparaben sodium salt.

[0127] <Example 11> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 7, except that benzylparaben was used instead of n-propylparaben sodium salt. <Example 12> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.895 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), n-propylparaben sodium salt (5 g), and ALKOX (trademark) L-11 (100 g) were used as raw materials.

[0129] <Example 13> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.895 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), n-propylparaben sodium salt (5 g), and sorbitol SG (100 g) were used as raw materials.

[0130] <Example 14> A pellet-shaped resin composition was obtained in the same manner as in Example 1, except that ECO FILM™ (7.995 kg) and Kuraray Poval™ 5-98 (2.00 kg) were used as raw materials. Then, n-propylparaben sodium salt (5 g) was dissolved in water in an amount such that the water content of the aqueous composition was 35% by mass. The resulting aqueous solution of n-propylparaben sodium salt was mixed with the pellet-shaped resin composition and allowed to absorb water, thereby obtaining an aqueous composition with a water content of 35%. A coated product was obtained from the aqueous composition in the same manner as in Example 1. Furthermore, a single-layer film was formed using the same process as in the production of the coated product, without using paper as the substrate, and the film was dried to obtain a sheet-shaped resin composition with a thickness of 100 μm.

[0131] <Comparative Example 1> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 7, except that ECO FILM (trademark) (1.599 kg) and National I 1658 (6.396 kg) were used as the starch. <Comparative Example 2> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (9.995 kg) and n-propylparaben sodium salt (5 g) were used as raw materials.

[0133] <Comparative Example 3> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (9.895 kg), Kuraray Poval (trademark) 5-98 (100 g), and n-propylparaben sodium salt (5 g) were used as raw materials.

[0134] Comparative Example 4 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (8,000 kg) and Kuraray Poval (trademark) 5-98 (2.00 kg) were used as raw materials.

[0135] Comparative Example 5 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (8,000 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and n-propylparaben sodium salt (0.1 g) were used as raw materials.

[0136] Comparative Example 6 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.980 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and n-propylparaben sodium salt (20 g) were used as raw materials.

[0137] Comparative Example 7 A sheet-shaped resin composition, a water-containing composition, and a coated material were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.800 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and Nano Ace (trademark) (200 g) were used as raw materials. <Comparative Example 8> A sheet-shaped resin composition, a water-containing composition and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.800 kg), Kuraray Poval (trademark) 5-98 (2.00 kg) and Metablen S-2030 (trademark) (200 g) were used as raw materials.

[0139] <Comparative Example 9> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.990 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and benzoic acid (10 g) were used as raw materials.

[0140] Comparative Example 1 (Good) A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.990 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and sorbic acid (10 g) were used as raw materials.

[0141] Comparative Example 11 A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.990 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and propionic acid (10 g) were used as raw materials.

[0142] Comparative Example 12 A sheet-shaped resin composition, a water-containing composition, and a coated material were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.990 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), and sodium benzoate (10 g) were used as raw materials.

[0143] <Comparative Example 13> Raw materials were ECO FILM (trademark) (7.790 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), sodium benzoate (10 g), and A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that Nano Ace (trademark) (200 g) was used. <Comparative Example 14> A sheet-shaped resin composition, a water-containing composition, and a coated article were obtained in the same manner as in Example 1, except that ECO FILM (trademark) (7.790 kg), Kuraray Poval (trademark) 5-98 (2.00 kg), sodium benzoate (10 g), and Metablen S-2030 (trademark) (200 g) were used as raw materials.

[0145] The coated articles obtained in Examples 2 to 13, like Example 1, had good appearances with no uneven thickness or foreign matter.

[0146] The impact strength, oxygen permeability (23°C • 50% RH), and color tone (b value) of the sheet-shaped resin compositions obtained in the Examples and Comparative Examples after 3 months of storage at a moisture content of 35±1% by mass are shown in Table 3. Table 3 also shows the average amylose content of modified starch (A) (referred to as average Am content) and the content of modified starch (A), the degree of salinity of polyvinyl alcohol (B), the viscosity in a 4% aqueous solution (20°C) and its content, and the type and content of added components [compound (C) or compounds other than (C) and their content, type and content of compound (D), and type and content of compound (E)]. The method of adding component (C) is also shown in Table 3.

[0147] As shown in Table 3, the resin compositions obtained in Examples 1 to 14 had significantly higher impact strength than all of Comparative Examples 1 to 14. The resin compositions obtained in Examples 2 to 7, 9 to 11, 13, and 14 had lower oxygen permeabilities than Comparative Examples 1 to 14, and the resin compositions obtained in Examples 1, 8, and 12 had lower oxygen permeabilities than Comparative Examples 1 to 3 and 6 to 14, and were confirmed to have oxygen permeabilities comparable to those of Comparative Examples 4 and 5. Therefore, it was found that the resin compositions obtained in Examples 1 to 14 had excellent impact strength and oxygen barrier properties. Furthermore, as shown in Table 3, it was confirmed that the resin compositions obtained in Examples 1 to 14 not only had excellent impact strength and oxygen barrier properties, but also had low b values ​​and excellent color tone, even after storage for 3 months in a water content of approximately 35% by mass.

[0148] A 20 0 1 / 2 cm PET sheet (Novaclear (trademark) A3020, manufactured by Mitsubishi Chemical Corporation) was laminated to both sides of the sheet-shaped resin composition obtained in Example 3 with an adhesive (a 1:1 (weight ratio) mixture of Takelac (trademark) A520 and Takenate (trademark) A50, manufactured by Mitsui Chemicals, Inc.) to obtain a laminate. A compressed air vacuum forming machine (FKS-0632-20, manufactured by Asano Laboratories, Inc.) was used to form the laminate at a heater temperature of 600°C, a sheet surface temperature of 120°C, a heating time of 10 seconds, and a forming pressure of 3 kg / cm. 2 The laminate was thermoformed under the conditions above into a cup (inner diameter 70 mm, height 110 mm). The obtained molded product had no cracks, uneven thickness, or cloudiness, and a cup with a good appearance was obtained.

[0149] 1 ... Water-containing pellets, 2 ■■·Single-screw extruder, 3 ■■·Film-forming die, 4 ■■·Water-containing composition, 5 Paper, 6 Covering material, 7 a Pressure roll (rubber), 7 b Cast roll (metal), 7 c Touch roll (rubber), 8 Twin-screw extruder, 9 Hopper, 10 Addition nozzle, 11 Resin temperature gauge, 12 Resin pressure gauge, 13 Adapter, 14 Die

Claims

1. 50 to 98 parts by weight of modified starch (A), 2 to 50 parts by weight of polyvinyl alcohol (B), and 0.01 to 0.15 parts by mass of formula (1): 【Chemical 1】 [In the formula, R １ represents an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms; R ２ ~R ５ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, or an alkoxy group having 1 to 12 carbon atoms; R ６ represents a hydroxyl group or an alkoxy group having 1 to 12 carbon atoms. or a salt thereof (C) wherein the total content of the components (A), (B), and (C) is 100 parts by mass, and the average amylose content of the modified starch (A) is 50% by mass or more.

2. In the formula (1), R １ The resin composition according to claim 1, wherein is an alkyl group having 1 to 6 carbon atoms or an aralkyl group having 7 to 9 carbon atoms.

3. 2. The resin composition according to claim 1, wherein the total content of the modified starch (A), the polyvinyl alcohol (B), and the compound represented by formula (1) or its salt (C) is 80 mass% or more relative to the mass of the resin composition.

4. The resin composition according to claim 1, wherein the modified starch (A) is at least one selected from the group consisting of etherified starch, esterified starch, cationized starch, and crosslinked starch.

5. 2. The resin composition according to claim 1, wherein the modified starch (A) is at least one selected from the group consisting of etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms and esterified starch having a structural unit derived from a dicarboxylic acid anhydride.

6. 2. The resin composition according to claim 1, wherein the polyvinyl alcohol (B) has a viscosity of 1 to 50 mPa·s at 20° C. as a 4% aqueous solution measured in accordance with JIS Z 8803.

7. 2. The resin composition according to claim 1, further comprising 0.1 to 10 parts by mass of a polyoxyalkylene (D) and / or 0.01 to 5 parts by mass of a polyol plasticizer (E), wherein the total content of the components (A), (B), (C), (D), and (E) is 100 parts by mass.

8. A water-containing composition comprising the resin composition according to claim 1, wherein the water content is 1 to 50 mass %.

9. A coated article obtained by coating the water-containing composition according to claim 8 on paper or film.

10. A multilayer structure comprising the coating of claim 9 and one or more layers (X).

11. A packaging material comprising the coating according to claim 9 or the multilayer structure according to claim 10.

12. 10. A method for producing the coated article according to claim 9, comprising the step of using an extruder to coat the aqueous composition according to claim 8 onto a film or paper transported by a take-off machine.

13. A film or sheet comprising the resin composition according to claim 1.

14. A laminate comprising the film or sheet of claim 13 and one or more layers (X).

15. A packaging tray or cup comprising the film or sheet of claim 13 or the laminate of claim 14.

16. 16. A method for producing a packaging tray or cup according to claim 15, comprising the steps of: molding the resin composition according to claim 1 using an extruder to obtain a film or sheet; laminating one or more layers (X) onto the obtained film or sheet to obtain a laminate; and thermoforming the obtained laminate into a packaging tray or cup.

17. The method for producing a resin composition according to claim 1, comprising a step of simultaneously mixing the compound represented by formula (1) or the salt thereof (C) with components other than (C).

18. 9. A method for producing the resin composition according to claim 1 or the water-containing composition according to claim 8, comprising the steps of: preparing a mixture by mixing components other than the compound represented by formula (1) or the salt thereof (C); adding an aqueous solution of the component (C) to the mixture; and optionally further drying the mixture.

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